Human Skeletal System
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| Bone Name | Quantity | Notes |
|---|---|---|
| Frontal | 1 | Forms the forehead and upper eye sockets |
| Parietal | 2 | Forms the sides and roof of the cranium |
| Temporal | 2 | Houses the ear structures; contains mastoid process |
| Occipital | 1 | Forms the back and base of the skull; contains foramen magnum |
| Sphenoid | 1 | Butterfly-shaped; forms part of the eye orbits and cranial floor |
| Ethmoid | 1 | Contributes to nasal cavity and eye orbits; contains cribriform plate |
| Bone Name | Quantity | Notes |
|---|---|---|
| Nasal | 2 | Forms the bridge of the nose |
| Maxilla | 2 | Upper jaw; forms part of the eye sockets and nasal cavity |
| Zygomatic | 2 | Cheekbones; forms part of the eye sockets |
| Mandible | 1 | Lower jaw; only movable bone of the skull |
| Lacrimal | 2 | Small bones forming part of the eye sockets; contains tear duct |
| Palatine | 2 | Forms part of the hard palate and nasal cavity |
| Inferior Nasal Concha | 2 | Scroll-like bones in the nasal cavity |
| Vomer | 1 | Forms part of the nasal septum |
| Bone Name | Quantity | Notes |
|---|---|---|
| Hyoid | 1 | U-shaped bone in the neck; supports the tongue; not attached to other bones |
| Bone Name | Quantity | Notes |
|---|---|---|
| Malleus | 2 | Hammer-shaped; in middle ear |
| Incus | 2 | Anvil-shaped; in middle ear |
| Stapes | 2 | Stirrup-shaped; in middle ear |
| Bone Name | Quantity | Notes |
|---|---|---|
| Cervical Vertebrae | 7 | C1 (atlas), C2 (axis), C3–C7; in the neck |
| Thoracic Vertebrae | 12 | T1–T12; articulate with ribs |
| Lumbar Vertebrae | 5 | L1–L5; in the lower back |
| Sacrum (fused sacral vertebrae) | 1 (5 fused) | Triangular bone; forms part of the pelvis |
| Coccyx (fused coccygeal vertebrae) | 1 (4 fused) | Tailbone; vestigial structure |
| Bone Name | Quantity | Notes |
|---|---|---|
| Ribs (True Ribs, 1–7) | 14 (7 pairs) | Directly connected to sternum via costal cartilage |
| Ribs (False Ribs, 8–10) | 6 (3 pairs) | Indirectly connected to sternum via shared cartilage |
| Ribs (Floating Ribs, 11–12) | 4 (2 pairs) | Not connected to sternum |
| Sternum (Manubrium, Body, Xiphoid Process) | 1 | Breastbone; consists of three fused parts |
| Bone Name | Quantity | Notes |
|---|---|---|
| Clavicle | 2 | Collarbone; connects arm to torso |
| Scapula | 2 | Shoulder blade; connects humerus to clavicle |
| Bone Name | Quantity | Notes |
|---|---|---|
| Humerus | 2 | Upper arm bone |
| Radius | 2 | Forearm bone (thumb side) |
| Ulna | 2 | Forearm bone (pinky side) |
| Carpals (Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate) | 16 (8 per hand) | Wrist bones |
| Metacarpals | 10 (5 per hand) | Bones of the palm |
| Phalanges (Proximal, Middle, Distal) | 28 (14 per hand) | Finger bones (3 per finger, 2 for thumb) |
| Bone Name | Quantity | Notes |
|---|---|---|
| Hip Bone (Ilium, Ischium, Pubis) | 2 | Each hip bone is formed by three fused bones; forms the pelvis |
| Bone Name | Quantity | Notes |
|---|---|---|
| Femur | 2 | Thigh bone; longest bone in the body |
| Patella | 2 | Kneecap; sesamoid bone embedded in tendon |
| Tibia | 2 | Shinbone; larger bone of the lower leg |
| Fibula | 2 | Smaller bone of the lower leg |
| Tarsals (Talus, Calcaneus, Navicular, Medial Cuneiform, Intermediate Cuneiform, Lateral Cuneiform, Cuboid) | 14 (7 per foot) | Ankle bones |
| Metatarsals | 10 (5 per foot) | Bones of the foot |
| Phalanges (Proximal, Middle, Distal) | 28 (14 per foot) | Toe bones (3 per toe, 2 for big toe) |
| Bone Name | Quantity | Notes |
|---|---|---|
| Sesamoid Bones (e.g., in tendons of hands, feet) | Varies | Small, round bones; number varies by individual |
| Sutural (Wormian) Bones | Varies | Small bones within skull sutures; number varies by individual |
Key Notes
- Total Bones: Approximately 206 in adults, though infants have more (around 270) due to unfused bones that later fuse (e.g., sacrum, coccyx, hip bones).
- Sesamoid Bones: Embedded in tendons (e.g., patella); their number varies. The patella is the largest and most consistent sesamoid bone.
- Sutural Bones: Small, irregular bones found in the sutures of the skull; not present in all individuals.
- Skull: Comprises 22 individual bones (excluding auditory ossicles), with 8 cranial and 14 facial bones.
- Vertebral Column: Consists of 26 separate bones in adults (7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, 1 coccyx).
- Ribs: 12 pairs total (7 true, 3 false, 2 floating).
MCQs
1. How many bones are typically found in an adult human skeleton?
2. Which bone is the only movable bone of the skull?
3. How many cervical vertebrae are in the human vertebral column?
4. Which bone is known as the collarbone?
5. What is the longest bone in the human body?
6. Which bone is not attached to any other bone in the body?
7. How many pairs of true ribs are there in the thoracic cage?
8. Which bone is also known as the kneecap?
9. How many carpal bones are in one wrist?
10. Which bone forms the back and base of the skull?
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